A Highly Sensitive Dual-Core Photonic Crystal Fiber Based on a Surface Plasmon Resonance Biosensor with Silver-Graphene Layer

A highly sensitive dual-core photonic crystal fiber based on a surface plasmon resonance (PCF-SPR) biosensor with a silver-graphene layer is described. The silver layer with a graphene coating not only prevents oxidation of the silver layer but also can improve the silver sensing performance due to the large surface-to-volume ratio of graphene. The dual-core PCF-SPR biosensor is numerically analyzed by the finite-element method (FEM). An average spectral sensitivity of 4350 nm/refractive index unit (RIU) in the sensing range between 1.39 and 1.42 and maximum spectral sensitivity of 10,000 nm/RIU in the sensing range between 1.43 and 1.46 are obtained, corresponding to a high resolution of 1 x 10(-6) RIU as a biosensor. Our analysis shows that the optical spectra of the PCF-SPR biosensor can be optimized by varying the structural parameters of the structure, suggesting promising applications in biological and biochemical detection.